Daniel Wakin, the Times's classical-music reporter, has a perceptive piece on singing high Cs, with some interesting comments from Florez. Wakin also touches on Duprez and Nourrit. The whole question of what Duprez's high C de poitrine was like is one of those mysteries that even the estimable Stefan Zucker may never be able to answer. People who are as fascinated by tenors--and by the remarkable Nourrit--as I am will enjoy Henry Pleasants's superb book, The Great Tenor Tragedy, which recounts Nourrit's disastrous last days, primarily in his own words.
Luciano Pavarotti - King of the High C’s - Opera - Music - New York Times